升级php7

1:
修改apt软件源
打开文件 /etc/apt/sources.list
添加以下行
deb http://packages.dotdeb.org jessie all

2:
Fetch the repository key and install it.

wget https://www.dotdeb.org/dotdeb.gpg
sudo apt-key add dotdeb.gpg

3:
sudo apt-get update

4:
sudo apt-get install php7.0-fpm
sudo apt-get install php7.0-mysql

apt-get install php-curl(升级后可能会缺乏这个扩展，须要从新安装一下)

若是使用symfony可能还要升级

sudo apt-get install php7.0-dom

5:
更新nginx socket path
vitual server中的 fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;

6:从新启动nginx与nginx fpm
service nginx restart
/etc/init.d/php7.0-fpm restart